docs: def pool_set(service, pool_name, key, value):
      """
      Sets a value for a RADOS pool in ceph.
      :param service: six.string_types. The Ceph user name to run the command under
      :param pool_name: six.string_types
      :param key: six.string_types
      :param value:
      :return: None.  Can raise CalledProcessError
      """
      cmd = ['ceph', '--id', service, 'osd', 'pool', 'set', pool_name, key,
             str(value).lower()]
      try:
          check_call(cmd)
      except CalledProcessError:
          raise